All of a sudden I have Lumia Denim...

Something weird has happened with my Lumia 1320. I recently purchased a Cricket branded 1320 for $50 from Crickets website and the first thing I did when it came was update it and then install the Preview for Developers app and update it as far as it would go (which is 8.1 update with Lumia Cyan). Once it was updated, I installed the Insiders app and upgraded to W10.

After a while, I was having some issues with screen tearing, so I decided to go back to W 8.1 and see if it was also doing it there. After going back, I again installed all the updates and the Preview for Developer updates. Again it updated to Cyan and then said it was up to date.

This past week, a friend of mine offered to buy the phone for $100, so I decided to sell it. Having never had a Windows Phone, he asked me to set it up for him. I did a factory reset and got it ready for him. Once all the updates were done, I was greeted with a "Welcome to Lumia Denim" message and my phone now says it has denim installed.

Maybe I am reading to much into it, but it seems very weird. Even on the Microsoft website and Cricket's FAQ, they list Cyan as the newest update for the Cricket 1320. Anyone know how this could have happened?